Hook tooth rotary drill bit and cutter



June 9, 1953 w, KAMMERER 2,641,447 I HOOK TOOTH ROTARY DRILL BIT ANDCUTTER Filed Jan. 9, 1950 2 Sheets-Sheet 1 Willi/[I111].

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\ 25 ARCHER 71514114445252;

' I N V EN TOR.

A 76- ENE).

June 9, 1953 A; w. KAMMERER HOOK TOOTH ROTARY DRILL BIT AND CUTTER 2Sheets-Sheet 2 Filed Jan. 9 1950 7 v! 5 if 7 ARCHER WJZIMMEEER,

IN VEN TOR.

BY M TTOZNEY- Patented June 9, 1953 Archer'wi, Kammercr, Fullertong fla'li'f mnmieatiamimuame, 1959)}Serifliltl'mt13'1g53flr (o1. ass-46yZGlalins. I", The; present invention relates:- to earthworms; tools ,1,and 1 more particularly. to. drill ibitslof the; rotary typeccapablev-ofproducing aibore holder:

of .Jreaming or enlarging existing bore holes. I,

An. object of thepresent invention is-tot pmvidelarotary drill. bit.embodying. an iinmovedl tOothedgauge-or. reaming roller cutter that-loanform. a. shoulder in. the. formation of such shapeasmto 'cbuperatelwiththe-cutterandltenditoxhold the latteriin an outward position during the.drill---. ing 4 operation. In this connection, .tlie1iorm of! the.shoulder produced .is such as ,to. minimize or, avoidthe tendency:offthe shoulder to break off: inadvertently under. the drilling. weight"imposed; on the cutter.

Another-objector. thewinvention is to-proyide atoethedside roller cutterfor. a: drill-bit that is; capable of hooking or keying, itself to, the:

formation, in order to "minimize or prevent/the: tendency for theformationrto force. the. cutter inwardly.

Another. obj ectof. the invention is; to, provide: animprovedflrotarydrill bithagving expansihle:

toothed roller. cutters ithat forml. a shoulder;

the: formation of such shape as, to. prevent the formation fromvtendingv tic-squ eze: the cutters:

inwardly; thereactive forces betweeii: the: shoule 2L; Eig. :53 is atcross-section taken along the slime: 5H5 on Eigl 1;, I

. Fig, 6 tafliragmentaryl section through oneot; the cutters. I

The 4 drill bit incorporating: the inventiom isdisclosedinltheedrawing-s :asbeing, of the-type described and claimedin: my applicatiom ion Expansible Rotary,- Drill. Bits,-.Serial No.13575535,,

" filed January- 9, 1950.

d'er and cutters, in fact, tending. to.- hold the cutters .in theirdesired iexpandingposition.

A further. object of the invention toiprovide a toothedroller cutter forarotary drilltbit of,

generally conoidah frusto-conical; or tapered. form, which a, greatertooth length iisavailaibles for operation-upon,theformation, and-in'which:.

the .pdepthof. tooth at: the small end of zthesouttor is made largerfor. greater formation penetration.

Another objector the inventioniisto provide a mtarydrillbititoothedfiroller cutter ofigenerally,

conoidaljorm, which enableslarger hearings be incorporated in: the bit for transmitting .1 t lqa'clsxto and from the cutter.

This invention possesses many: :otheradizamta'ges, andhasother objectswhich may be made; more-clearly apparent from a consideration offi'fashown the drawings accornpanying'- formingspart .ofthepresentspeoifibationt Itfwill traeted' position;

Fig: Zita-View Sim-name 1; witli'tlie cuttersr in expanded' pos-itienyFig; 3 f is' anenlarged section through 7 one off tha toothedroller"cutters and its supporting bearing;

Fig. 4 is a" oross section taken" along" the line- Al-J on Fig. 2,"

It is to he understood?" howerers that l the invention may embodied inother types,andspecificlformsaof drill .bits.-.

As show/n'in the drawings, the drill-hi-t-A is'Of-i the: expansiblehole: enlarging type: whiolzvcan beattached :to the -:lower end of l as.string; of drill pipe Bibr loweringv through a well rcasinglstringg;(not shown), in order to enlarge thewellsborer below the casing lshoe(not-shown). The -.dri'1l bitiCllttGfs-JD are-initially held :inretracted position; but they; can be: eirpandedl outwardlyg for thepurposesof producing anlaimular formation; shoulder C. in the well.bore:- upon-.whichathe cutters can continue to. operate; forrthecmlrmseeof enlargingthe diameter oftthe-well bore the desired length 1 of hole.

The drill bitwincludes an l-elongate-mainzbodyz I l. in --whichr amandrel- IZ is telesconeds p er portion-offtlie :mandrel is constituted:a ikelly: l 3 -having;a= threaded pin I Mscrewed iintoz a sub .15whichrmaya-formithedowermosta-portionl of the drill uipestring Bl The;kelly or. drill stem member. I Stitself: isaslidablygsplined intheauppervportionnflthe body; I 1-, as by forming-zthelexteriorr lfi ot:the'kelly-of 1: hexagonal shapeufitting within a.-.corresponding-;hexagenaldoody secketflw The;

kel-lyt member has an external flange-l 81; received: withinvtheebody;servingmhe pumose-sof holding: the drill stemmember ltrtherewithinTby'engagmg; aretainer ring-2,18: disposed mtertl'xermember:alcove 'its rfiamre l8 iandusecuredto:the'aendiof thesbody; asbytlie"aidioftweldingt material 20; I

The 'll hasiai longitudinally extending;

transversei slot? 2311' in. which pair of' opposed cutter" supp rtingmembers: 2 2 are-- disposed? 'lheseesupportmgimembers havetheir upperends: mounted on pivot or hinge pins 23 suitabl'y so cured to tlie body:The cuttersupportiiig members or legs 7&2" each have a bearingsupporting pin" 2 G at thes'lower end on which a roller side;-

geugeor reamingicutter l 5):" is-rotatably mounted: Anti-friction ibearing elements v are -disposedllie--= tween eao hl'ibearing Isupporting pin fl t-and cutter It to reduce the friction therebetween:Thus; roller bearingelement's ZWare mounted on'a'roller race "26* on thepin and are-- received w-itliim an opposedcutterrraoe-QT? These-bearingelements 25- serve-"to transmit a substantial portion' of the radialloads betweentlre'pin24 androller cutter Ill? Ball'- bearing' elements"28? are disposed between a ball ra'ce i li' in-the cutter; arrangediimWardly of "the-roller "races-2 6, 2 1 and an opposed raceflll in thebeariiig supporting' in-224i, The ball element's' 2'8transmit :part'iof"the radial fload's;

end a substantial portion ,ofthe axial loads b'etween the cutter andbearing pin. the ball bearing elements 28 retain the cutter Ill itaddition,

on the pin 24, by preventing its axial movement a i with respect theretoin both directions.

The roller bearing elements'25 are inserted-on the pin race 25 and thecutter N then slid over the end of the pin until its roller-race 2 1. isdis- The balls 28 may then be inserted through a passage 3| in the pinposed fully over the rollers.

between the cutter II and pin ball races 29, 30, whereupon the passagemay be closed by a suitable plug 32 welded, or otherwise suitablysecured, to the pin 24. In this manner, the balls 28 are held in properposition between the ball races 29, 3Q, securing the cutter properlyonthe thecutters I, their supporting legs 22 are swung outwardly about thehinge pins 23 to a predeter mined extent.

The cutters are expanded through the aid of a lowertubular member 33forming part ofthe mandrel [2. This member is piloted within a lowersocket 34 in the kelly 53. A swivel connection assembles the kelly l3and lower tubular member 33 together for jointlong'itudinal movement,while permitting relative angular movement therebetween. Such swivelconnection may'take the form of ball bearing elements 35 mounted inopposed races 36, '37 'onth'e lower member 33 and kelly 13, theballsbe'ing' inserted through'a passage 38 extending through the kelly flangel8, and being prevented from inadvertent removal from the'ball races bya pas sage plug 35, that is prevented from outward movement by engagingthe main bit body I l l The lower tubular member 33extends downwardlyfrom its swivel portion and through'a thrust and guide member 40 restingupon a body shoulder 4!. This thrust member initially is disposed belowthe lower end of the kelly I3,

to allow the mandrel I2 to be moved downwardly, for the purpose ofeffecting outwardimovement of the cutters II, and resisting-theiriinwardmovement. The lower end of the tubular member 33 is slidable in a lowerguide collar'42 integral with the body-H and forming a support resistinglateral movement or deflection of the j tubular member 33.

The tubular member is provided with a cupshaped thrust head 43intermediate the upper and lower guides 40, 42, having a depending skirt4-4 terminating above a thrust block 46 slidable along the exterior ofthe mandrel member 33 below the skirt. The block v4,63 is longitudinallyslotted oil-opposite sides of the mandrel in alignment with the cuttersupporting legs 22, to carry a pin 41 on each side of the tubular memberon which the upper end of an inclined thrust link 48 is pivoted. Thelower end of this link 48 is pin connected to a supporting leg 22.

The cutters it are expandible outwardly upon hinge pins 23 through theagency of: the thrust links 48. If desired, outward expansion of thecutters l0 and their supporting legs 22 may be accomplished by a helicalcompression spring 49 .disposed'withinthe skirt 44 and bearing upon '5the thrust head 43 and thrust block 46. apparent that this spring 49tends to urge the It is thrust block 46 downwardly and the legs 22 inflan outward direction.

The cutters It may be locked in retracted position by a holding plate 58having holes 5| receiving the lower ends of the ball retaining plugs 32.The plate 50 will prevent outward expansion of the cutters l0 untilremoved from the plugs 32. Such removal is eifected hydraulically bysecuring a central rod 52 to the plate and projecting it upwardly intothe central passage 53 formed throughthe mandrel. A ball 54 may bedisposed in the passage, the ball having a diameter substantially equalto the diameter of the'passage, in order to function as a piston andenable fluid under pressure within the drill pipe downward movement ofthe mandrel 12 with re- I spect to the body H, which causes the lowerend of the thrust skirt 44 to engage the block 46 and ment swings thelegs 22 outwardly about their B and drill bit A to force the central rod52 down-- wardly and remove the holding plate 50 from bore, with theparts occupying the position illustrated most clearly in Fig. 1, inwhich the holding plate 50 secures the cutters It in retracted,position, and with the spring 48 (when a spring is used) under maximumcompression. The tubular mandrel I2 is disposed upwardly of the body II,as limited by engagement of its kelly flange it with the retainer ringl9. Ihe assembled tool is then lowered through the we'l1 casing to aposition below thecasing shoe at which the underreaming or holeenlarging operation is to commence. v

When this location is reached, the pumps at the top of thewell bore arestarted and thefluid in the drill pipe B and bit A is subjected topressure. Such pressure acts upon the ball 54 and forces both the balland the central rod 52 out of the passage 53, which removes the holdingplate 50 from the plug elements 32 and allows the en-' tire holdingdevice to be ejected from the bit.

Following removal of the holding device, the

spring 49 is allowed to expand, urging the thrust block 46, downwardlyand, through the thrust links 48, swinging the cutter legs 22 abouttheir,

hinge pins 23 in an outward direction, in order to force the cutters [0against the formation wall. The drill pipe and the rotary .drill bit arero-.

members 22 and cutters Ill outwardly to an extent limited by engagementof the thrust block 46 with the upper end of the lower body guide 42. lWhen the thrust block has reached this lowermost position within thebody, the cutters have been expanded outwardly to their maximum extent.

With the formation shoulder C having been "formed, the drill pipe B maybe lowered,'which "latter member to the body I l, and from the body; andhinge pins 23 to the cutter supporting legs 22 v and cutters l0. .Withthe imposition of the proper drilling weight, the drill pipeB and tool Acan be rotated, to roll the cutters I around the formation shoulder Cand cause them to dig into the latter.

Each cutter I0- is of generally conoidal or conical form, in order toproduce and operate upon an annular formation shoulder transversely ofthe hole axis, during rolling of the cutters thereupon. The cutter hasperipherally arranged teeth 60, the base portions 6! of which aresomewhat concave, which is also true of the outer ends 62 of each tooth.The back cone or heel 63 of each tooth is adapted to engage the wall ofthe enlarged hole and determine the reaming diameter of the tool. Eachtooth operates upon the formation shoulder along the tooth length andeffects its removal by the usual chipping, tearing or chiseling actioncommon to such teeth.

Each tooth at its back cone or heel portion 63 is extended outwardtransversely of the cutter, to provide a hook 64 which will dig into theformation and produce an annular groove D in the shoulder when thecutter i0 is in its expanded position. This hook portion 64 of the toothhas an outer edge 65 which is inclined in a downward and outwarddirection when the cutter is in its fully expanded position, forming acorresponding inclined annular surface in the formation shoulder C. Inview of this direction of inclination, the reactive forces between thecutter teeth 60 and the formation shoulder C tend to urge the cuttersoutwardly, but the cutters cannot move beyond the maximum position towhich they have been expanded, because of the engagement of the thrustblock 46 with the lower body guide 42.

If the cutter teeth of the cone cutter were formed in the usual mannerof bevel gear teeth, the height of each tooth 60 at the smaller end 66of the cutter would be comparatively small. As a result, the extent ofpenetration of the teeth into the formation would also be small.Moreover, the formation of the cutter teeth in the fashion of bevel gearteeth would bring the base portions of the teeth closer to the axis 61of the cutter and would require the entire bearing structure between thecutter and pin to be made correspondingly smaller, because of thenecessity for having adequate material between the bases of the cutterteeth and the ball race 29.

The foregoing arrangement is depicted in Fig. 6, in which the usualbevel gear type of cutter tooth is shown by the dashed lines 10, H,which necessitates the roller and ball races 21, 29 of the cutter l0 andbearing pin 24 to be made of a substantially smaller radius, asindicated by the broken lines 12.

By curving or deviating the base I3 and the outer end portions 14 of theteeth at the small end 66 of the cutter away from and outwardly of thenormal base cone of the cutter, the teeth at the small cutter end 66 aredisposed outwardly to a greater extent from the axis 61 of the cutter,allowing the ball and roller cutter races to have a much greater radiusthan was heretofore provided, as shown in full lines in Fig. 6, Thus,the increase in the diameters of the roller and ball cutter races 21, 29enables the bearing supporting pin 24 and its races 26, 30 to be made ofa corresponding greater diameter, increasing the load carrying capacityof the bearing supporting pins considerably, and allowing larger balland roller bearing elements 28, 25 to be used, with their attendantgreater load carrying capacities.

It is apparent that the deviation of the cutter teeth 60 at the smallerend 66 of the cutter away 1' from the cutter base cone l0 axis, or froma nornormal conical position, not only provides a greater height oftooth at this region of the cutter, but also allows larger bearings tobe used in the cutter.

The curvature of the teeth away from the base cone 10 provides stillanother important advantage. As described above, the outer portions 64of the teeth hook or key into the formation by forming the shouldergroove D, and thereby tend to hold the cutters in their outwardposition. The tooth portions at the smaller end 66 of the cutter producea. formation shoulder portion E, when the cutters H! are in theiroutwardly expanded position which, is inclined in a downward and inwarddirection. This inner portion E of the shoulder makes an obtuse anglewith the smaller diameter wall of the well bore. As a result, thecutters do not have any tendency for breaking down through the formationwall because of the drilling weight, which might tend to cause rifiingof the well bore. The convex shape which the cutters produce in theformation tends to stabilize the cutters on the shoulder and cause theirteeth 60 to roll around the formation shoulder, for the purpose ofcutting it away uniformly and progressively in a downward direction.

The inventor claims:

1. A conical side roller cutter for a rotary well drilling bit havingperipheral teeth extending from the large end of the cutter to its smallend, the base portions of the teeth at the small end of the cutter beingdisposed outwardly of the normal base cone of the cutter and the toothportions at the large end of the cutter having their outer endsextending transversely outward to a greatly increased extent beyond theouter ends of the adjacent intermediate tooth portions, the depth ofeach tooth portion at the large end of the cutter being greatlyincreased over the depth of each intermediate tooth portion, the outerend portion of each. tooth at the large end of the cutter being inclinedto the axis of rotation of the cutter to a greater extent than the outerend of each intermediate tooth portion or the cutter, whereby the toothportions at the large end of the cutter form hooks with the back coneportions of said teeth.

2. conical side roller cutter for a rotary well drilhng bit havingperiphera1 teeth extending from the large end of the cutter to its smallend, the base portions of the teeth at the small end of the cutter beingdisposed outwardly of the normal base cone of the cutter andthe toothportions at the large end of the cutter having their outer endsextending transversely outward to a greatly increased extent beyond theouter ends of the adjacent intermediate tooth portions, the depth ofeach tooth portion at the large end of the cutter being greatlyincreased over the depth of each intermediate tooth portion, whereby thetooth portions at the large end of the cutter form hooks with the backcone portions of said teeth, the outer ends and bases of the cutterteeth being concave lengthwise of the teeth.

ARCHER W. KAMMERER.

References Cited in the file of this patent UNITED STATES PATENTS Number

